1. Field of the Invention
The invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device having a metal gate.
2. Description of the Prior Art
In the integrated circuit (IC), electrical connection between different semiconductor devices are constructed by contact structures such as contact plugs and interconnection structures. However, along with the miniaturization of the IC, reduction of the feature size, and progress in fabrication of semiconductor device, the line width of interconnections and the feature size of semiconductor devices have been continuously shrunk. With this trend, any misalignment occurs at contact plugs fabrication process may cause contact plug shift issue and even cause short circuit within a device or between devices. In one circumstance that agate structure and a source/drain of one device are electrically connected due to contact plug shift, a short circuit occurs within the device and thus the device is failed. In another circumstance that the short circuit occurs at different devices, the whole IC may be failed.
Therefore, a method for manufacturing a semiconductor device that is able to prevent device failure due to contact plug shift issue is still in need.